A marine engine system may include an engine with a combustion chamber to burn air and fuel to produce power, a cooling system for cooling the engine and various other engine system components. The cooling system of a typical marine engine system may use untreated or raw water, for example, seawater, as coolant to cool engine system components. In normal operation, cooling water may be drawn by a water pump into the cooling system via a water inlet, such as a seacock or a valve. Since a body of water may contain various types of matter and foreign objects such as seaweed, marine life, dissolved mineral, shell, plastic object, and debris, it is possible that such matter and/or foreign objects may enter the cooling system and create a blockage. Flow could also be blocked if a rubber impeller in a typical sea water pump fails or becomes jammed by a foreign object. Such a blockage could cause flow reduction, or a complete shut-off of cooling water flow. This, in turn, can lead to overheating of the engine and other components relying on cooling water. Even a relatively moderate blockage could cause poor component performance and result in more frequent maintenance.
To prevent a blockage in water flow, various strainers have been used at the water inlet to prevent entry of foreign objects. However, even with the use of strainers, blockage still can occur over time. For example, some material and/or foreign objects may still make their way into the cooling system and cause a blockage or flow reduction, or the strainer itself could be blocked. In-line flow detectors have been used to detect flow reduction. However, such intrusive devices may themselves affect flow. It is desirable to have timely detection of a reduction in flow of cooling water so that appropriate actions can be taken to prevent damage to marine engine system components and improve operating efficiency.
One attempt to detect a reduction in cooling water flow is described in U.S. Pat. No. 4,630,036 (the '036 patent) issued to Ford on Dec. 16, 1986. The '036 patent discloses a warning system that detects a reduction of cooling water flow by monitoring a resistance ground signal generated by a sensing element inserted into the cooling system. The various embodiments disclosed in the '036 patent include a sensing element that is intrusive to existing cooling system components.
While the '036 patent may provide for detecting cooling water flow rate reduction, the system disclosed in the '036 patent includes sensors that must be installed in the engine exhaust system. The exhaust system passageway must be breached to allow mounting of the sensors. As a result, the system may be complicated to install, and the intrusive sensor may itself interfere with flow and may be damaged by material such as debris in the cooling water.
The system and method of the present disclosure are directed toward improvements in the existing technology.